Safety-tread



J. W. SCOTT AND T. H. GREER.

SAFETY TREAD.

APPLICATION FILED MAR.26| 1919.

7710mm. Greer Patented Apr. 27, 1920.

. 3 vwewtom John mllliimswfl' '1. w. SCOTT AND T. H. GREEIR. SAFETY TREAD.

APPLICATION FILED MAR. 26, 1919. 1,338,332. Patented Apr. 27, 1920.

2 $HEET3-3HEET 2- UNITED STATES PATENT OFFICE.

JOHN WILLIAM SCOTT, OF BAYSIDE, NEW YORK, AND THOMAS HOAG GREEK, OF BLOOMFIELD, NEW JERSEY.

SAFETY-TREAD.

Specification of Letters Patent. Patented Apr. 27, 1920.

Application filed March 26, 1919. Serial No. 285,325.

T 0 all whom it may concern:

Be it known that we, JOHN WILLIAM SCOTT and THOMAS H. GREEK, citizens of the United States, residing, respectively, at Bayside, Queens (10., N. Y., and Bloomfield, Essex county, New Jersey, have invented new and useful Improvements in Safety- Treads, of which the following is a specification.

This invention relates to safety {tread structures for floors, stairs, inclined ways and the like and consists of an improved and novel arrangement and construction thereof, which is particularly adapted to facilitate the replacement and renewal of the safety treads when they become worn and to permit of this renewal with the minimum expense both as to material and the labor required therefor.

The objects and advantages of our present invention are more fully understood by comparison with the standard type of safety treads which heretofore had extensive commercial use particularly in connection with subway and elevated railway operation. As is well known the factor of safety in connection with such installations is an important one, and it is the universal practice to employ non-slip tread surfaces particularly upon stairs and where subjected to considerable wear it has been the common practice to employ various forms of separable nonslip or safety treads which are detachably secured to the stair treads or supports so as to permit of their being replaced with new safety treads when they become worn to the danger point. These separable safety treads in the present standardized practice are formed of suitable non-slip material such as steel having incorporated therewith lead or other non-slip material and are installed upon the stair treads in suitable lengths corresponding to the width of the stair and approximately the full width thereof so that in the standard practice upon wearing out of the tread the unit to be replaced is of substantial length, as aforesaid corresponding to the full width of the stair treads. However, it is found in practice that in many situations particularly in turns in stair ways and where a hand rail is present that the wear upon the safety tread is to a large degree localized with the result that the safety treads become worn through and dangerous in one spot or on one side thereof which necessitates the removal and replacing of the full width safety tread unit. Obviously this practice is accompanied by considerable waste of material which adds to the cost of maintenance.

The improved safety tread of the present invention is designed particularly with a view to avoiding the aforesaid waste incident to replacements and to that end consists of a safety tread construction embodying a plurality of safety tread blocks or insert units of reduced size and an improved arrangement for facilitating the removal and renewal of the smaller non-slip insert units. Accordingly, in the preferred embodiment of our invention there is employed a suitable supporting or safety tread frame adapted to have detachably secured thereto tread blocks or inserts of non-slip material and formed to provide the tread surface, these blocks being of suitable size to permit of the removal and replacement of just that local tread surface which has become worn so as to reduce the waste to the very minimum and to effect a corresponding saving in maintaining an effective non-slip tread surface. Further important features of our present invention reside in an improved construction and relative arrangement of the parts whereby the non-slip insert blocks are securely and firmly supported in position in a manner whereby the individual blocks may be quickly and conveniently replaced and further in the improved form of block employed which is capable of' being positioned upon the frame so as to present a new surface thereof at the front or nosing portion of the safety tread at which point the greatest wear occurs. This latter improved feature is valuable and offers a further advantage .in that the safety tread blocks may be shifted in position so as to obtain the greatest efficiency from the individual blocks and thereby further contribute to the economy effected.

The foregoing and other advantages of our improved tread will be understood by reference to the accompanying drawings wherein desirable embodiments of our invention are illustrated and wherein like reference characters of this description are applied to corresponding parts in the several views.

Referring to the drawings Figure 1 is a plan view of a desirable construction of a further modification wherein our im' proved safety tread inserts are detachably secured directly to a cast iron stair tread in the manner of our invention.

In Figs. 1,2 and 3 we have shown an approved embodiment of the features of our inblocks with the key portionsfitted within 'vention in a detachable safety tread for stair ways which is adapted as a whole to be secured to the tread member of a stair by suitable screws or bolts. The safety tread as shown comprises a supporting frame 1 of metal which may desirably be cast iron or steel in the form of a skeleton frame for the sake of lightness and economy of metal. This frame 1 is desirably composed of front and rear marginal members or bars 2 and 3 and side marginal'members 4:, 4L and intermediate connecting members 5, 5 desirably equi-distantly spaced as shown and connecting the marginal members 1 and 2. The rear and side marginal members are desirably formed as shown with upturned vertical flanges 6 and the forward member 1 is formed with a depending vertical flange 7. The described arrangement provides rectangular openings or sockets 8, 8 intermediate of the frame bars 5, 5 inclosed by the forward and rearward marginal frame' members 2 and 3. With relation to each of the sockets or openings 8, in the supporting frame, safety tread inserts or blocks of suit-' able non-slip material are 7 provided and adapted to provide the treadsurface; these safety tread blocks 10 are here shown of rectangular form and supported at their marginal edges upon the frame bars inclosing the openings 8 and the tread blocksare furtherprovided on their under sides with a key portion enlargement 11 closely fitting the openings or sockets 8 ofthe frame. By this arrangement upon positioningthe tread the sockets the shoulders or ledges of the key portion by engaging the inner walls of V the openings will'effectually prevent lateral movement and displacement; of the tread inserts. v

For the purpose of detachably securing the tread blocks in proper position upon the frame the side edged portions of the blocks may desirably be t9 pered or inclined as illustrated and to co-act therewith suitable key bars 13 are provided and adapted to be clamp the latter upon the frame when secured thereto. As shown the key bars are forwardly and rearwardly extended and are desirably of channel form throughout their length and are of corresponding height to that of the tread blocks so that their upper surfaces are level therewith and said bars as shown are detachably secured in position by suitable screws 14, 14 fitting apertures therein and threaded into the frame 1.

As will be obvious the key bars 13 when secured in position on the. frame will operate to securely clamp the tread blocks upon the frameby engagement with the adjacent side portions of the blocks. This arrangement affords an effective means for securing the blocks in position and one which permits of the individual blocks being readily and conveniently removed when desired by simply taking out the two securing screws as shown. The channel form of key bars employed is desirable in that the channeling 7 provides for drainage which is particularly 8 desirable in some locations, lightens the metal employed, at the same time maintain ing a substantial depth thereof and further by the arrangement of the securing screws ent invention consists in the proportioning and-relative arrangement of the tread blocks with reference to the frame and in the inrproved form thereof whichpermits of these tread blocks being reversible in position; i To this end the tread'blocks 10 are formed to correspond'at both their forward and rearward portions as shown being formed wit'h rounded off edge or nosing portions 15. The V securing sockets 8, 8 and the 'key'portion 11 of the tread blocks; are so positioned rela V tively that they will properly determine-the position of the rounded ends 15 of the tread I 7 block so that these rounded edges or nosings 15 will assume a corresponding position at the front edge of the frame upon the re-' versal of the block.

As will be readily appreciate'd'the non-slip" i tread blocks or inserts 10 may be composed of any suitable non-slip material or, compositions such as a bonding material having an abrasive substance incorporated therein such as oxid of aluminum, carbid of sili- 9 fl u Or en lls' h ts rial may be of suitable cement or equivalent or these blocks may be made of lead or alloy which may have abrasive grains incorporated therein or they may be in the form of tiles of vitreous material with suitable abrasive particles combined therewith. Or as will be further understood these non-slip tread blocks may be formed of sections of any of the present types of non-slip treads and from the latter it follows that treads of the standard types when partially worn may be sawed into blocks of the form here shown and the good portions utilized in connection with my improved tread structure shown.

As illustrated the front and rear end portions of the key bars are of a form corresponding to the contour of the front and rear ends of the tread blocks. The key bars, as shown, extending to the forward edge of the tread block offer protection to the latter in that they provide a bearing for the foot immediately adjacent the corners of the tread blocks at which point there is obviously the greatest danger of fracture. A further advantage of the. desirable form of key bar shown is that this key bar is also reversible in its position in similar manner to the blocks so that when the forward portion thereof becomes worn it may be reversed in position to derive a renewed nosing portion.

lVhile we have shown and described an approved form of our invention it will be understood that the same is subject to various modifications without departing from the scope of the invention. For instance in Figs. 4, 5, and 6 we have shown suitable modified forms thereof embodying the features and advantages of our improved tread as described in structures of differing form and arrangement.

In Fig. 4; a suitable modified safety tread is illustrated corresponding closely to the form of Fig. 1 but wherein the securing means for the tread blocks is shown to consist of key members or clips 18 corresponding to sections of the described key bars 10. These clips are suitably secured in position by means of screws 19 passed therethrough and threaded into the frame 1 corresponding to the method of securing the key bars 10 of the first described construction. The tread blocks as shown in corresponding manner are secured in position by the inclined side walls of the clips .18 and intermediate of the clips the blocks are provided with abutting lateral extensions.

In Fig. 5 there is shown a desirable modified form particularly adapted for flooring treads. As here disclosed it is designed that the tread blocks are of rectangular form and adapted to be secured to the floor by key bars of the form in cross section as de; scribed. As here shown the key bars maybe made up as an integral member having key bar sections 21, 21 in crossed and right angular relation. As illustrated in this arrangement the securing screws for the key bars may be centrally arranged of the key members whereby the latter are securely positioned by means of a single securing screw 22. o

In Fig. 6 we have shown a further desirable embodiment of our improved features incorporated in a cast iron stair tread structure. As here illustrated the stair tread member 24: is formed to generally correspond to the safety tread frame member 1 heretofore described, by having the upper surface thereof formed with a suitable depression 25 adapted to receive therein the tread blocks of our invention. This depressed portion of the stair tread is as shown formed with a series of socket depressions 26 adapted to coact with and receive therein the key portions 11 of our improved tread blocks. The detachable tread blocks or inserts as shown are secured in position by key bars 13 corresponding to the arrangement of the first described disclosure. This construction of Fig. 6 thus illustrates the manner in which the improved features of our invention may be embodied in a permanent stair tread structure or installation as distinguished from the separable safety tread of Fig. 1.

We claim:

1. A safety tread comprising a metallic supporting frame adapted to be secured upon a stair tread, a plurality of tread blocks of non-slip material supported upon the frame with their side edge portions in close proximity and detachable key mem bers interposed between the tread blocks and formed to overlie portions of the latter to secure the blocks in position, said key members being arranged transversely to permit removal of any one of the tread blocks without disturbing the major area of the tread surface.

2. A safety tread comprising a metallic supporting frame adapted to be secured upon a stair tread, tread blocks of non-slip material supported in plural arrangement longitudinally on the frame with their side edge portions in close proximity and deone or the other of the nosing portions at the forward edge of the frame.

3. A safety stair tread comprising a metallic supporting frame adapted to be secured upon a stair tread, tread blocks of non-slip material arranged in plural arrangement longitudinally of and supported upon the frame with their side edge portions in close proximity and detachable key members interposed between the tread blocks and extending transversely of the frame, said key members being formed to overlie portions of the tread blocks to secure upon a stair tread structure, a plurality of tread blocks of non-slip material supported upon the frame member with their side edges in close proximity, said tread blocks being of substantially the full depth of the frame and having nosing edges, formed thereon both at their forward and rearward edges, securing'key bars interposed between the tread blocks and formed to overlie por- V tions of the blocks to secure them in position, means detachable to secure the key bars to the frame, said key bars being arranged to extend transversely of the frame to per- 7 mit removal of local areas of the tread blocks without disturbance to the major area of the tread surface and to be co-extensive with the tread blocks to protect the forward 7 5. A safety tread comprising a metallic supporting frame adapted to be secured upon a stalr tread or supportlng surface, said frame belng of skeleton form havlng a series of openings or pockets arranged longitudinally thereof, tread blocks of non-slip material arranged to have bearing support upon the frame and provided with keypor tions fitting the frame openings and key members detachably secured .to the frame and arranged to overlie portions of the blocks to secure thelatter in position, said key members being arranged transversely ofthe frame to permit removal of individual blocks without disturbing the major portions of the tread surface and provided with longitudinal channels for drainage of the tread surface, said tread blocks being formed with nosing portions at their forward and rearward edges and the frame and blocks being relatively formedto'permit of the blocks being reversed to position one or the other of the nosing portions at the for- 'ward' edge of the frame, substantially as described.

In testimony whereof We have signed our names to this specification.

JOHN WILLIAM scor'r.

THOMAS HOAG GREEK. V V 

